Converting from BD file structure to standard DVD.
 

I've a few BD movies for my kids, they want to watch them while in the car. What are the tools needed to do this conversion? I need to shrink the movie down from at least 25 GB to less than 4.7 GB to fit on a standard DVD blank. These are BD movies that I already paid for, and the downgraded versions I'm thinking of making will be for my family's own use, don't want to get in a sticky situation here.

Thanks,